Keywords:
Pulmonary vessels, CT-Angiography, Contrast agent-intravenous, Imaging sequences, Technical aspects, Embolism / Thrombosis
Authors:
S. Do, K. Dobeli, C. Hacking; Herston, QLD/AU
DOI:
10.26044/ranzcr2021/R-0515
Purpose
Pulmonary embolism (PE) is a potentially life-threatening condition, mandating urgent diagnosis and treatment [1]. Computed Tomography Pulmonary Angiogram (CTPA) is the preferred diagnostic modality for PE, however nondiagnostic examination remains the most important drawback [2,3].
Spectral detector CT (SDCT) is a new dual energy acquisition technology where a single x-ray tube potential is applied and two layers of detectors separate low and higher energies [4]. This gives the ability to generate virtual monoenergetic images (VMI), synthesizing data as if the patient was scanned using a single photon energy x-ray beam [5]. Previous studies have shown increased pulmonary vasculature contrast opacification using 40 keV VMI, as the active energy (kV) of the x-ray beam falls within the region of maximal absorption (K-edge) of iodine (33.2 keV) [6]. This improved opacification may reduce the number of nondiagnostic CTPA studies [7,8].
The aim of this study was to examine CTPA nondiagnostic rates in relation to pulmonary trunk attenuation (HU) on standard polyenergetic (120 kVp) and VMI (45 keV) for patients referred for PE on SDCT at the Royal Brisbane and Women’s Hospital.